1. Field of the Invention
The present invention relates to a hybrid vehicle which is equipped with two kinds or more of prime movers for running a vehicle.
2. Related Art
In the prior art, there is a hybrid vehicle which is intended by combining two kinds or more kinds of prime movers to improve an overall efficiency while exploiting the merits of the individual prime movers and compensating the demerits. One example of this hybrid vehicle is disclosed in JP-A-7-186748.
The disclosed hybrid vehicle employs an engine and an electric motor as the prime movers of the two kinds and is constructed such that the drive force of the engine is transmitted to either the front wheels or the rear wheels whereas the drive force of the motor is transmitted to the wheels to which is not transmitted the drive force of the engine.
On the other hand, this hybrid vehicle is equipped with a controller for controlling its running state. To this controller, there are inputted a variety of signals which indicate the running states including the RPM and throttle opening of the engine, the steering angle, the depression of the brake pedal, the depression of the accelerator pedal and the gear position. The controller controls the motor to assist the drive force by the motor at an acceleration or deceleration when the vehicle runs straight or at a small steering angle.
However, what is performed by the hybrid vehicle, as disclosed in the aforementioned Laid-Open publication, is to compensate the shortage of the drive force of the engine with the rotational drive of tile motor on the basis of the various signals, as inputted to the controller, at an acceleration or deceleration when the vehicle runs straight or at a small steering angle. In other words, the drive force of the motor is simply used to assist the drive force of the engine, but the control cannot satisfy the specific running state, as intended by the driver. Thus, it cannot be said that the hybrid vehicle sufficiently exploits the motor for improving the running performance and the drivability.
A primary object of the present invention is to provide a hybrid vehicle which can exploit the drive force of one prime mover effectively, while the other prime mover is active, on the basis of the specific running state, as intended by the driver.
Another object of the present invention is to decide a demand of the driver on the basis of a behavior of the vehicle so that the other prime mover may be controlled to satisfy the demand.
In order to achieve these objects, therefore, the hybrid vehicle of the present invention is provided with: means for detecting the active state of an action unit to be activated by the driver; means for detecting the behavior of the vehicle; means for deciding whether or not the vehicle behavior is identical to the demand of the driver; and means for controlling another prime mover to satisfy the demand of the driver.
The action unit includes a brake unit and a throttle unit for controlling the output of an engine, and another prime mover includes a motor-generator, for example. Thus, if the vehicle speed does not drop although a braking is active, a braking force is established by the motor-generator so that the demand for the braking can be satisfied unless the driver does any further braking operation. On the contrary, if the vehicle speed or acceleration is not raised although the engine output is increased by controlling the throttle, the motor-generator can be activated to increase the drive force as the entirety of the vehicle thereby to satisfy the driver. Moreover, if it is intended to block the movement of the vehicle in the directed, as not intended by the driver, at a start of the vehicle on a slope, the vehicle is kept in the stopped state by the output torque of the motor-generator. As a result, the vehicle can be easily started on the slope.
The above and further objects and novel features of the present invention will more fully appear from the following detailed description when the same is read with reference to the accompanying drawings. It is to be expressly understood, however, that the drawings are for the purpose of illustration only and are not intended as a definition of the limits of the invention.